Discussion: When is on in? Control circles

When making up control descriptions when is a second identical feature that is either;

1. on the control circle line
or
2. straddling the circle line but edging into the control circle

described in third column on the clue sheet/control description sheet?

Does cutting the circle to expose the identical feature change the decision?

This came up when course setting this weekend.

Not sure if I can answer the direct question, but this line seems relevant:

"However, a good control is found primarily by map reading. Descriptions and codes can assist in this task, but should be kept as short and simple as is necessary to locate the control.

Note: Control descriptions should not be used to correct map errors"

taken from this IOF specifications pdf

I would suggest that if there might be confusion when map reading or when in the area near the control then you might want to use the extra column in the control description sheet. If there's minimal risk of confusion then you don't need to bother.

Cutting the circle should not make a difference.

The 2004 Control Description document (link above) states:

Column C - Which of any similar feature
This column is used when there is more than one similar feature within the control circle; e.g. south eastern.

To be 100% fussy, I would say "on the line is not within". In practice, I would err on the side of caution and add the symbol to column C.

Cutting the circle would make it harder to detect "in-or-out", so I would add the symbol.

2 comments:

1. If it is clearly outside the circle, I definitely would not add a column C.

2. I am extra fussy that the exact description be repeated for both features. If the clue is trail-trail-junction (one instance only) and there are two trail-trail-crossings in the circle, the clue is trail-trail-junction only. The problem is if you've got two or more things that can be mistaken: stream-ditch-junction v. stream-gully-junction. In the past I have been "extra fussy" and not used column C, but I felt it might not have survived a protest.

I think column C is really a relic from the days of overprinting. With modern printing technology the circle is not going to be mistaken for being centered on a similar feature that is on the line. That said, a good principle in any ambiguous situation is to move the control to an unambiguous location, if possible, and avoid any controversy.

When it's not otherwise obvious.

That said, a good principle in any ambiguous situation is to move the control to an unambiguous location, if possible, and avoid any controversy.

Do you mean to say if there were a number of boulders within the circle, that you'd not put a control there? That would remove 90% of control locations on our local maps.

Well, then, I guess you have a lot of situations where it's not possible.

Terrain too complex? Then don't use it!

Um, that's not what I said.

My approach would be to break the circle, the orienteer needs to see as much as is possible. by doing that, they will be able to see that there are two nearby features mapped the same.
Column 3 I would use only if both objects were within the circle ,ie the circle would be solid.